Charles Ellicott Commentary Isaiah 7:18

"And it shall come to pass in that day, that Jehovah will hiss for the fly that is in the uttermost part of the rivers of Egypt, and for the bee that is in the land of Assyria." — Isaiah 7:18 (ASV)

The Lord shall hiss for the fly ... — See the Note on Isaiah 5:26 for this phrase. The legions of Egypt are represented by the flies that swarmed on the banks of the Nile (Exodus 8:24, and possibly Isaiah 18:1), those of Assyria by the bees of their forests and their hills (Deuteronomy 1:44; Psalms 118:12).

The mention of Egypt indicates that some of the king’s counselors were then, as afterwards (Isaiah 18:2; Isaiah 31:1), planning an Egyptian alliance, while others were relying on that with Assyria. The prophet tells them that each alliance is fraught with danger. No help and much evil would come from such plans. Consistent in his policy from first to last, the one counsel he gives is that people should practice righteousness and wait upon the Lord.

The uttermost part of the rivers of Egypt. — This phrase points to the whole extent of the Delta of the Nile, probably to the whole Egyptian course of the Nile itself. Historically, the prophecy found its fulfillment in the invasion of Pharaoh Necho in the reign of Josiah (2 Kings 23:29), or, nearer Isaiah’s time, in the movements of Tirhakah’s armies (2 Kings 19:9).